<template>
    <div>
       <router-link tag='div' to='/' class="header-abs" v-show='showAbs'>
           <div class="iconfont header-abs-back">&#xe624;</div>
       </router-link>
       <div class="header-fixed" v-show='!showAbs' :style="opacityStyle">
           <router-link  to='/' >
                <div class="iconfont header-fixed-back">&#xe624;</div>
            </router-link>
            景点详情
       </div>
    </div>
</template>
<script>

export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>
<style lang="stylus" scoped>
    @import '~styles/varibles.styl'
    .header-abs
        position absolute
        left .2rem
        top .2rem
        width .8rem
        height .8rem
        border-radius .4rem
        line-height .8rem
        text-align center
        background rgba(0, 0, 0, .8rem)
        .header-abs-back
            color #fff
            font-size .4rem
    .header-fixed
        z-index 2
        position fixed
        top 0
        left 0
        right 0
        bottom 0
        height $headerHeight
        line-height $headerHeight
        text-align center
        color #ffffff
        background $bgColor
        font-size .32rem
        .header-fixed-back
            position absolute
            top 0
            left 0
            width: .64rem
            text-align: center
            font-size: .4rem
            color #fff
</style>
